Correctly color items depending on focus.

Perspex.Themes.Default/ListBoxItemStyle.cs

@@ -27,6 +27,13 @@ namespace Perspex.Themes.Default
                     },
                 },
                 new Style(x => x.OfType<ListBoxItem>().Class("selected").Template().Name("border"))
+                {
+                    Setters = new[]
+                    {
+                        new Setter(ListBoxItem.BackgroundProperty, new SolidColorBrush(0xfff0f0f0)),
+                    },
+                },
+                new Style(x => x.OfType<ListBoxItem>().Class("selected").Class(":focus").Template().Name("border"))
                 {
                     Setters = new[]
                     {

Perspex.Themes.Default/TreeViewItemStyle.cs

@@ -38,6 +38,13 @@ namespace Perspex.Themes.Default
                     },
                 },
                 new Style(x => x.OfType<TreeViewItem>().Class("selected").Template().Name("header"))
+                {
+                    Setters = new[]
+                    {
+                        new Setter(TreeViewItem.BackgroundProperty, new SolidColorBrush(0xfff0f0f0)),
+                    },
+                },
+                new Style(x => x.OfType<TreeViewItem>().Class("selected").Class(":focus").Template().Name("header"))
                 {
                     Setters = new[]
                     {